This invention relates broadly to a method of winding an A.C. generator stator.
As vehicles generally become more compact and comfortable to drive, three-phase A.C. generators tend to become more compact and produce a higher output thereby requiring a higher packing ratio of the coil to be fitted into stator slots and a shorter winding time in order to reduce the production cost.
In, for example, Japanese Laid Open patent application No. 55804/1975, a concentrated winding method for winding a three-phase A.C. generator stator is proposed wherein one coil, having a predetermined number of turns, is inserted into a stator slot by a coil inserting jig.
A disadvantage of the above proposed method resides in the fact that the winding method does not provide a sufficiently high coil packing ratio.
In, for example, Japanese patent Laid Open application No. 136161/1981, a split winding method is proposed which provides for a high coil packing ratio by inserting split coils one by one into a staggered array of stator slots when a winding is effected.
However, a disadvantage of the last proposed method resides in the fact that a considerable winding time is required.
While Offenlegungschrift 23 48 641 proposes a split multi-layered wave winding and FIG. 5 herein illustrates how the current follows the wave winding, the publication does not illustrate a specific winding method.
The present invention relates to a method of winding a three-phase A.C. generator stator which provides a high coil packing ratio and shortens the winding time.
The present invention splits a stator coil for one phase into groups to form two lap wound coils or two wave wound coils per phase, then staggers the split wound coils by a predetermined pitch, fits them in advance to a coil inserting jig and thereafter simultaneously inserts these coils into stator slots with the coil inserting jig.
The two wound coils of the first, second and third phases are inserted into the slots of a stator in the manner described hereinabove. The two wound coils of the second and third phases are respectively inserted into the slots of the stator after the two wound coils of the first phase are arranged in the slots of the stator. Consequently, a coil packing ratio within the slots of the stator is increased as compared with prior art constructions.